Labeling proteins with small molecules by site-specific posttranslational modification

J Am Chem Soc. 2004 Jun 30;126(25):7754-5. doi: 10.1021/ja047749k.


We report here the development of a general strategy for site-specific labeling of proteins with small molecules by posttranslational modification enzyme, phosphopantetheinyl transferase Sfp. The target proteins are expressed as fusions to the peptide carrier protein (PCP) excised from nonribosomal peptide synthetase, and Sfp catalyzes the covalent modification of a specific serine residue on PCP by the small molecule-phosphopantetheinyl conjugate. The labeling reaction proceeds with high specificity and efficiency, targeting PCP fusion proteins in the cell lysate. The PCP tag has been shown to be compatible with various proteins, and Sfp-catalyzed PCP modification, compatible with various small-molecule probes conjugated to coenzyme A, highlighting the potential of the PCP tag for site-specific protein labeling with small molecules.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Avidin / chemistry
  • Binding Sites
  • Biotin / chemistry*
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism
  • Fluorescence
  • Molecular Structure
  • Peptide Synthases / genetics
  • Peptide Synthases / metabolism
  • Protein Processing, Post-Translational*
  • Recombinant Fusion Proteins / chemistry*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Staining and Labeling


  • Carrier Proteins
  • Recombinant Fusion Proteins
  • Avidin
  • Biotin
  • Peptide Synthases